Felling machines are commonly used in the apparel industry for sewing two parallel series of stitches, or stitchings simultaneously. Such parallel stitchings are typically formed by use of two needles and two loopers for forming chain stitches. The felling machine can be used to close a "tube" formed from one or more pieces of material where the parallel stitchings are sewn at or near opposed edges of the tube. Felling machines are also commonly used to join two separate pieces of overlapped material. The inseams and outseams of blue jeans, for example, are usually joined by double stitchings sewn with a felling machine. The double stitchings enhance the strength and durability of the seams.
Felling machines of the conventional type mechanically link the needles with the loopers so that the needles and loopers are synchronized to form stitches. The mechanical linkages are carried through what is known as an "arm" with a "throat" being defined by the open space area created between the arm and the needles. In felling machines used for sewing blue jeans, a "folder" device is positioned in the throat area. The felling machine operator feeds two separate pieces of denim material into the folder which produces an overlapping fold at the edges of the two denim pieces. The folded materials are then fed to the sewing area of the felling machine which joins the materials by placing two parallel stitchings along the fold.
The ergonomic and functional disadvantages of conventional felling machines are numerous and easily appreciated. The felling machine arm is an obstruction and constant source of noise, heat, and failure due to its high number of mechanical parts. Sewing speed is limited by the inertia and friction created by the mechanical linkages. To maintain higher machine operating speeds, the length of the machine arm and throat is kept to a minimum. Power is needed to accelerate and decelerate the mechanical linkages. The mechanical linkages must be lubricated periodically. The minimal amount of working space available to the operator for feeding materials into the folder demands that the operator use unnatural and stressful positioning of the hands and body in order to adequately feed the folder. Carpal tunnel syndrome is a common medical problem among felling machine operators.
Therefore, there is a need for a felling machine which employs physical and mechanical separation of the needle head and loopers.